BACKGROUND: No somatic treatment has been found to be
effective for chronic fatigue syndrome (CFS). Antidepressant
therapy is commonly used. Fluoxetine is recommended in
preference to tricyclic agents because it has fewer sedative
and autonomic nervous system effects. However, there have been
no randomised, placebo-controlled, double-blind studies
showing the effectiveness of antidepressant therapy in CFS. We
have carried out such a study to assess the effect of
fluoxetine in depressed and non-depressed CFS patients.

METHODS: In this randomised, double-blind study, we recruited
44 patients to the depressed CFS group, and 52 to the
non-depressed CFS group. In each group participants were
randomly assigned to receive either fluoxetine (20 mg once
daily) or placebo for 8 weeks. The effect of fluoxetine was
assessed by questionnaires, self-observation lists, standard
neuropsychological tests, and a motion-sensing device
(Actometer), which were applied on the day treatment started
and on the last day.

FINDINGS: The two groups were well
matched in terms of age, sex distribution, employment and
marital status, and duration of CFS. There were no significant
differences between the placebo and fluoxetine-treated groups
in the change during the 8-week treatment period for any
dimension of CFS. There was no change in subjective
assessments of fatigue, severity of depression, functional
impairment, sleep disturbances, neuropsychological function,
cognitions, or physical activity in the depressed or the
non-depressed subgroup.

INTERPRETATION: Fluoxetine in a 20 mg
daily dose does not have a beneficial effect on any
characteristic of CFS. The lack of effect of fluoxetine on
depressive symptoms in CFS suggests that processes underlying
the presentation of depressive symptoms in CFS may differ from
those in patients with major depressive disorder.

MCM: 20 mg/day does not have a beneficial effect on any
characteristic of CFS."The lack of effect of fluoxetine on
depressive symptoms in CFS suggets that processes underlying
the presentation of depressive symptoms in CFS may differ from
those in pts w major depressive disorder.